Conventional light emitting semi-conductor (LES) devices (LESDs), including light emitting diodes (LEDs) and laser diodes, and packages containing LESDs have several drawbacks. High power LESDs generate a substantial amount of heat that must be managed. Thermal management deals with problems arising from heat dissipation and thermal stresses, which is currently a key factor in limiting the performances of light-emitting diodes.
In general, LES devices are commonly prone to damage caused by buildup of heat generated from within the devices, as well as heat from sunlight in the case of outside lighting applications. Excessive heat buildup can cause deterioration of the materials used in the LES devices, such as encapsulants for the LESDs. When LEDS are attached to flexible-circuit laminates, which may also include other electrical components, the heat dissipation problems are greatly increased.
Additionally, conventional LES devices and packages tend to be thick, which limits their uses in low form factor applications. Consequently, there is a continuing need to improve the design of flexible LES devices and packages to improve their thermal dissipation properties, as well as to allow for their use in low form factors.
Vias in multilayer circuits are used to electrically connect circuit layers that are separated by an insulating material. US 2003/0039106 discloses a double-sided wiring board having an electric connection between the two wiring layers with the use of a via. The electric connection is made more reliable by removing debris from the interface of the two wiring layers in the recess.